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Dimensional Analysis and Scale-Up
Published in Ron Darby, Raj P. Chhabra, Chemical Engineering Fluid Mechanics, 2016
The size of liquid droplets produced by a spray nozzle depends upon the nozzle diameter, the fluid velocity, and the fluid properties (which may, under some circumstances, include surface tension). Determine an appropriate set of dimensionless groups for this system.You want to know what size droplets will be generated by a fuel oil nozzle with a diameter of 0.5 mm at an oil velocity of 10 m/s. The oil has a viscosity of 10 cP, a SG of 0.82, and a surface tension of 35 dyn/cm. You have a nozzle in the lab with a nozzle diameter of 0.2 mm that you want to use in a lab experiment to find the answer. Can you use the same fuel oil in the lab test as in the field? If not, why not?If the only fluid you have is water, tell how you would design the lab experiment. Note: water has a viscosity of 1 cP and a SG of 1, but its surface tension can be varied by adding small amounts of surfactant that does not affect the viscosity or density.Determine what conditions you would use in the lab, what you would measure, and the relationship between the measured and unknown droplet diameters.
Dimensional Analysis and Dynamic Similitude
Published in William S. Janna, Introduction to Fluid Mechanics, Sixth Edition, 2020
A pneumatic spray nozzle is a two-fluid device that directs high-velocity air at a liquid jet to break the liquid into a spray. The average droplet diameter D of the spray depends on the mass flow rate of air m˙, the volume flow of liquid Q, the density of each fluid ρa and ρ1, and the difference in velocity of the two streams ∆V. Use dimensional analysis to derive a relationship for D.
Mixing carbon nanotubes with asphalt binder through a foaming process toward high-performance warm mix asphalt (WMA)
Published in International Journal of Pavement Engineering, 2022
Mehdi Zadshir, Fangliang Chen, Xiaokong Yu, Xin He, Irene Nigro, Maddalena Ricciarelli, Filippo Ubertini, Huiming Yin
The foaming method is accomplished by spraying a small amount of liquid foaming agent (either pure distilled water, ethanol-based CNT solutions, or commercial dispersant-based CNT solutions) into the binder via a nozzle embedded in the wall of the functioning chamber. When the hot binder comes into contact with a liquid droplet at the ambient temperature, it exchanges energy with the surface of the liquid droplet by heating the droplet to a vapor state. This process results in explosive expansion of the droplets and generates a large amount of steam bubbles. The steam bubbles are forced into the continuous phase of the binder under air pressure in the expansion chamber. With emission from the spray nozzle, the encapsulated steam expands until a thin film of a slightly cooler binder holds the bubble intact through its surface tension. This process occurs for a multitude of asphalt bubbles and thus, produces a foamed asphalt binder.
Combustion and emission characteristics of a common rail diesel engine fueled with reformed diesel/palm oil/gasoline blend fuels
Published in International Journal of Green Energy, 2019
Hao Chen, Jingjing He, Limin Geng, Xuan Zhao, Jing Ma
The cold filter plugging point of palm oil is 23ºC, the freezing temperature is 5ºC and the kinematic viscosity at 20ºC is 79 mm2/s. The fluidity and the low-temperature performance of palm oil are extremely poor. Remarkably high viscosity of palm oil will cause the coking and carbon deposition in the spray nozzle and the surface of combustion chamber. Also, it certainly worsens the atomization quality of fuel spray and thereby negatively affects the combustion process. Further, most of palm oil compositions are heavy distillates. When the distillation temperatures of palm oil are tested, the distilled fuel becomes white smoke in the distillation flasks and condensation tubes instead of normal droplets. Accordingly, it can be qualitatively concluded that palm oil has very high distillation temperatures and thereby very lower volatility. On the whole, palm oil has unfavorable properties used as vehicle fuel.
Performance evaluation of poly-urethane foam packed-bed chemical scrubber for the oxidative absorption of NH3 and H2S gases
Published in Journal of Environmental Science and Health, Part A, 2018
Grace M. Nisola, Kris Niño G. Valdehuesa, Alex V. Anonas, Kristine Rose M. Ramos, Won-Keun Lee, Wook-Jin Chung
Each acryl packed column had a diameter of 10 cm, a height of 80 cm and a total working volume of V = 3.93 L (bed height = 50 cm). Each column was randomly packed with PU cubes having 1 cm × 1.5 cm × 2 cm dimensions. On its upper portion, a polyvinyl chloride (PVC) spray nozzle was installed to deliver the scrubbing solutions, which were re-circulated continuously from the chemical feed reservoir and sprayed down on the packed bed. Counter-currently, the feed gas entered the bottom of the chemical scrubbers, wherein the flow rate was fixed at 10 L/min by gas flow meters (Koflok Model RK1600R). The treated gases exited on top of the columns. The chemical composition of the scrubbing liquid for each type of gas is listed in Table 1.